Research with clinically anxious adults has revealed that they estimate future negative events as far more likely to occur, relative to healthy controls. In addition, anxious adults estimate that such events are more likely to happen to themselves than to others. Previous research with anxious children and adolescents, in contrast, has revealed no increased probability estimates for negative events, relative to controls, and the events were rated as more likely to happen to others than to the self. The present study followed up these discrepant findings by investigating probability judgements concerning future negative events generated by children and adolescents who had actually experienced an extreme negative event and who met criteria for a diagnosis of Post-traumatic Stress Disorder ( PTSD). Control groups comprised a group of healthy participants, and a group of healthy participants whose parents had experienced a trauma and who met criteria for PTSD. The results revealed no overall differences between the clinical group and the controls. However, children and adolescents with PTSD estimated all negative events as significantly more likely to happen to others than to themselves, with this other-referent bias being strongest for events matched to their trauma. In contrast, the two control groups exhibited an other-referent bias for physically threatening events but not for socially threatening ones. Developmental analyses indicated that the strength of the relationship between anxiety and elevated judgements about future negative events declined with age in the control participants but that there was no significant relationship in the groups who had been exposed to trauma. The findings are discussed in the context of the literature on information processing biases and PTSD.